Chemical processing and oil refinery equipment become contaminated during use with oil and solid deposits, such as coke or iron sulfide. As the processing equipment normally consists of a closed vessel, the typical procedure for cleaning the vessel is to circulate a cleaning solution through the vessel in an attempt to emulsify the oily materials and dissolve the hydrocarbon binders to dislodge the solid particles. The flow of the cleaning solution will then act to flush the residue from the vessel.
It has been found that a cleaning solution which includes the combination of enzymes and a surfactant is extremely effective in removing oil and solid deposits, such as coke or iron sulfide, from industrial processing equipment, as well as from industrial machinery. Not only is this combination of ingredients effective in removing oil and dissolving the binder that binds the coke or iron sulfide particles, but it also has the advantage that when the residual cleaning solution is maintained in a quiescent state, the oil will separate from the water phase, so that the oil can be readily removed from the solution.
It has also been found that the effectiveness of the cleaning solution containing enzymes and a surfactant is increased as the cleaning solution is heated to an elevated temperature. However, when the temperature approaches the boiling point, i.e. 212.degree. F. the solution will boil and due to the presence of the surfactant, tremendous quantities of foam are generated in the cleaning system. The large quantities of foam can cause cavitation of the circulating pump, with the result that the cleaning solution cannot be effectively pumped through the equipment to be cleaned.